package y23.May;

import java.util.Scanner;

public class Factorial {
    public static long Fac(int n) {
        if (n == 0) {
            return 1;
        }
        else {
            return n*Fac(n - 1);
        }
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int a = scanner.nextInt();
        System.out.println(a+"的阶乘为"+Fac(a));
    }
}
